Mariani J, Changeux J P
J Neurobiol. 1980;11(1):41-50. doi: 10.1002/neu.480110106.
Intracellular recordings from Purkinje cells (PC) in the cerebellum of adult staggerer mutant mice revealed that the orthodromic response of PCs to juxtafastigial (JF) stimulation closely resembled a climbing fiber response (CFR). However, for most of the PCs studied, these responses were graded in a stepwise manner when the stimulus strength was increased. The underlying excitatory synaptic potentials (EPSPs) had the typical shape of EPSPs mediated through climbing fibers (CFs), but their size fluctuated in discrete steps, the highest one reaching the firing level. In the same PCs, the size of the spontaneous EPSPs fluctuated in a similar fashion and the frequency of each step was in the range of CF-mediated EPSPs. These results strongly suggest that in staggerer mice several CFs synapse with each PC instead of a single CF as in normal adults. Furthermore, the activation through some of these CFs does not reach the firing level of the corresponding PC.
对成年蹒跚突变小鼠小脑浦肯野细胞(PC)进行的细胞内记录显示,浦肯野细胞对顶核旁(JF)刺激的顺行反应与攀爬纤维反应(CFR)非常相似。然而,对于大多数所研究的浦肯野细胞,当刺激强度增加时,这些反应呈阶梯式分级。潜在的兴奋性突触后电位(EPSP)具有通过攀爬纤维(CF)介导的EPSP的典型形状,但其大小以离散步骤波动,最高值达到放电水平。在同一浦肯野细胞中,自发EPSP的大小以类似方式波动,并且每个步骤的频率处于CF介导的EPSP范围内。这些结果强烈表明,在蹒跚小鼠中,每个浦肯野细胞与多个攀爬纤维形成突触,而不像正常成年小鼠那样与单个攀爬纤维形成突触。此外,通过其中一些攀爬纤维的激活未达到相应浦肯野细胞的放电水平。